I agree mate, mine is the same as that without the perch.
Th magpie was on the top of the box with it's head lowered to the hole.
Pretty sure if they knew the lid was hinged they'd be strong enough to gain access that way.
It only takes a couple of hours for the chicks to starve to death, as they need constant feeding and can starve even if one of the parents bites the dust, as the remaining parent can`t feed them quickly enough.
I hate Magpies with a passion, but they`re so clever,
They sit on the tv aerials on the houses at the back of ours, which gives them a panoramic view of about a dozen gardens,
I`ve watched them from an upstairs window, as they follow the flight path of birds in and out of the gardens and then they go down onto the fences and shrubs, investigating where they`ve seen the parent birds go to. If there`s chicks they give themselves away, by their cheeping and once the Magpie knows that they`re there, it`s the end of them. Even if it`s a nest box, they just wait for them to stick their heads out and pick them off one by one.
One year, I laced a load of hens eggs with rat poison and put them on the shed roof. It must`ve got them, as the eggs went and the Magpies vanished during the breeding season.
However, when they invariably turned back up again and I put more baited eggs on the roof, the eggs didn`t get touched and I saw them looking at them from the vantage points too. It`s almost like stuff gets passed on amongst them.
It`s the same with the air gun too, I`ve shot a couple, but the rest of them seem to somehow learn, that the sight of someone in an upstairs window means danger and they scarper the moment they see any movement.
A lad I know has a Harris Hawks and that`s the only thing I know that is guaranteed to keep them away, as they don`t go near his back where the aviary that he keeps the Hawks in.
I`m surprised as many birds fledge as they do tbh.